.page{
    display: block;
    width: 100vw;
    height: 100vh;
    position: relative;
}
canvas {
    display: block;
    width: 100vw;
    height: 100vh;
}
.box{
    width: 300px;
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}